Aircraft cabin pressurizing and air conditioning apparatus



Oct. 21, 1952 F c. MARCHANT EIAL 2,614,815

AIRCRAFT CABIN PRESSURIZING AND AIR CONDITIONING APPARATUS Filed Jan. 19, 1948 a AMMQWM N m P 7 A5 A M W QM m N m M AW w ma J0 Patented Oct. 21, 1952 'UNlTED STATES PATENT OFFICE. AIRCRAFT cAmNrnEssUnIziNG AND AIR CONDITIONING APPARATUS Francis Charles Ivor Mar chant and Gordon Manns Lewis, Bristol, England, assignors toThe Bristol Aeroplane Company Limited, Bristol, England, a British company Application January 19, 1948, Serial No. 3,094: In Great Britain January 20, 1947 1 This invention concerns apparatus for maintaining in an aircraft cabin a pressure which is greater than the. atmosphericpressure when the aircraft is in flight above a selected altitude. This apparatus iscommonly referredto'as cabinpressurizing apparatus and thisspecification. 1 i l The object of the present invention is to provide an apparatus which affords a wide range of temperature of the pressurizing air without unduly increasing the number of parts (and hence the weight)" of the apparatus and also means for adjusting the de-humidification of the air.

Hitherto, this range of temperature has been obtained by providing in the apparatus either a cooler or a combustion or exhaust-gasheater. The former heater incorporates a fuel burner and the latter heaterhas the exhaust-gases from an engine passed through'it in heat-exchange relationship with the pressurized air.

-More specifically this invention has for its object to eliminate such heaters whilst enabling the pressurized air to be heated.

The invention relates tocabin pressurizing apparatus of the type in which the air is compressed, passed through acooler and delivered therefrom to the cabin.

According to the present invention cabin pres- 1 Claim. (Cl. 2579) will. be so called in a valve 6. The'intake 5 leads to a two-stage primary compressor 'l'fwhich is driven throughda multi-speed gear box8 by a motor (not shown), the input shaft ofthe gear box beingindicated at 9. Air from the compressor 1 is delivered to a duct In which leads to an assembly ll comprising-a re-heater I2 and a primary cooler I3. The air from the duct Hlpasses in succession through the units l2 and I3, that is, through the re-heater and then the cooler. i The compressed air leaving the assembly passes along main duct l4, l5 to the cabin 16. The duct l4 communicates with a by-pass conduit l'l leading to the re-heater l2. The passage of air from the duct [4 to the conduit I1 is controlled by a valve l8. r a V i It will be clear from the above description that the air delivered by the compressor 1 passes through the assembly II and thence byduct 14 towards the cabin [6. By suitably adjusting the valve [8 the quantity of air flowing along, the

duct l5 and conduit I! may be varied. "Thus, the quantity of the total air delivered to the cabin it which passes through the re-heater l2 is'var iable. 1

The duct 14 also communicates with a further by-pass conduit l9 which leads to a secondary surizing apparatus of the type set forth is characterised inthat the air'delivered by the cooler is capable of being brought into heat-exchange relationship with the compression-heated air delivered from said compressor thereby to regulate the temperature of the air entering the cabin.

According to a feature of the present invention the cooler and the re-heater together constitute a unitary assembly through which the compressed air passes from the re-heater to the cooler. V

There may be a valve to regulate the quantity of compressed air passing from the cooler respectively' direct to the cabin and through the reheater. i

The delivery side of the cooler may optionally be connected to a second cooler whose delivery is adapted to be passed to the cabin either direct or through the re-heater.

A practical application of the invention will now be described, by way of example, with reference to the accompanying drawing which shows a schematic layout of a cabin pressure apparatus in accordance with the present invention.

Referring to the drawing: air enters the cabin pressurizing apparatus by an intake 5, the quantity of air being suitably controlled by means of i cooler generally indicated by the reference numeral 20. The quantity of air passing along the duct [4 and conduit I9 is regulated by the valve 2| the arrangement being that as this valve is closed a greater quantity of air enters the conduit l9 and passes through the cooler 20.

The secondary cooler 2|] comprises a secondary compressor 22 to which the air from the conduit I9 is delivered, a heat exchanger 23 to which the compressor 22 delivers and aturbine 24 to which the heat exchanger. 23 delivers. The discharge from theturbine 24 is led back by a duct 25 to the duct I4 at the downstream side of the The turbine 24 drives the compressor 22 and as a consequence the air in passing through it does work at the expense of its heat content. The air is thus cooled to a temperature below the ambient air temperature and in so doing the temperature is lowered to below its dew point. The moisture in the air is therefore extracted on the delivery side of the secondary bient air and the passage of the air through each air delivered by the compressor 1 passes through 4 i the cooler and under certain circumstances it may be necessary to have this air over-cooled ,10 so that its moisture content may be reducedto a predetermined amount. This over-cooling isperformed by passing the air from the assembly H through the secondary cooler 20'. As a consequence of the over-cooling the moisture may be:

effectively and readily extracted in the water separator 26. The over-cooled air islat toolow a temperature for direct delivery to the cabin l6 and accordingly a part of the air, after water extraction, is passed through the re-heater l2 where .itzis :heated -bythe compressed air from thellgcompressor l. By'su-itably adjusting the valve;;l8 .the temperature of the airentering the cabin'z'lfit may be varied to aa-suitable value.

- .='1lpparatus for: pressurizing "and conditioning air to.';be.tlelivered tothe cabin 16 'of an aeroplane compr-is'ingta 1-primarycompressor 1 to draw air from the :ambientatmosphere and deliver it under pressure at a high temperature, a reheater l2, aadu-ct lllzto convey air irom said compressor-to thelreheater, a primary cooler 13 to receive the compressed :air from the .reheater,-aduct to-deliver ambient air 10'. said primary cooler to pass in heat exchange relationship-with compressed air from said reheater, valve means 21 to regulate the quantity =:of ambient :air passing through the primary cooler,.a"mainduct (i4, Hi) to convey compressed :air from the "primary cooler directly to'ftheacab'in, az-conduitfl'l to bypass said'main 'duct'zand conveyi'compressed'air from the'primary coolerindirectlytothe cabin by way of the re- 4 heater said compressed air passing in heat exchange relationship with the heated compressed air passing from the primary compressor to the primary cooler, a valve means IE to regulate the quantity of air going to theggcabin directly and also indirectly through the reheater, a secondary cooler 20, a conduit (i9, 25) to bypass said main .duct and convey compressed air from the primary cooler to the secondarycooler and thence to said V reheater, a secondary-cooler valve 2| to regulate the quantity of compressed air passing around the secondary-cooler bypass which air is over cooled in the secondary cooler to lower its temperature below-ambient air temperature "and its dew point, and a water separator 26 in the secondary-cooler bypass to remove moisture from the air delivered by the secondary cooler to the reheater, said reheater raising the temperature of therair delivered by the water separator prior to its introduction into the cabin.

FRANCIS CHARLES IVOR MARCI-IANT. ;GORDON vlVI-ANNS LEWIS.

I RE ERENCES .CITED.

The following references are of record in -the fileiofthis patent:

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